protected virtual void OnGaugeChanged(AngularGauge old, AngularGauge newValue)
{
}
protected override void OnVisualParentChanged(DependencyObject oldParent)
{
this.Gauge = this.VisualAncestors().OfType<AngularGauge>().FirstOrDefault();
base.OnVisualParentChanged(oldParent);
}